PowerShell两个参数中的任何一个都可以为null,但不能同时为null [英] PowerShell two parameters either of them can be null but not both null
问题描述
我想知道是否可以在参数级别而不是代码中完成: 我有2个参数:$ School和$ Class
I'm wondering if this can be done at the parameter level rather in code: I have 2 parameter: $School and $Class
Get-Students -School SchooName # Will give me all Students name in all classes in that School
Get-Students -Class ClassName # Will give me all Students name in that Class across all schools
Get-Students # Should return parameter level error.
我尝试使用以下内容:
function Get-Students{
param(
[parameter(ParameterSetName="School no null")]
[ValidateNotNullOrEmpty()]
[string]$School,
[parameter(ParameterSetName="School no null")]
[AllowNull()]
[string]$Class,
[parameter(ParameterSetName="Class no null")]
[AllowNull()]
[string]$School,
[parameter(ParameterSetName="Class no null")]
[ValidateNotNullOrEmpty()]
[string]$Class
)
}
但是这种方式不起作用...
But it doesn't work in this way...
希望我正确地解释了这一点.或者,如果没有办法只能通过代码内部的参数来做到这一点?
Hope I explained this correctly. Or if there is no way can do this from parameter only inside of the code?
谢谢 河
推荐答案
Updated. The following commented code snippet is based on Add a parameter to multiple Parameter Sets article. Allows supplying -Class
or -School
parameter or both of them all together.
function Get-Students{
param(
[parameter(Mandatory=$false)][switch]$SomeThing, # any type instead of [switch]
# ↑↑↑ parameter(s) in all Parameter Sets
[parameter(Mandatory=$true, ParameterSetName="School No Null")]
[parameter(Mandatory=$true, ParameterSetName="Class And School")]
[ValidateNotNullOrEmpty()]
[string]$School,
[parameter(Mandatory=$true, ParameterSetName="Class No Null")]
[parameter(Mandatory=$true, ParameterSetName="Class And School")]
[ValidateNotNullOrEmpty()]
[string]$Class
)
Write-Host $PsCmdlet.ParameterSetName -ForegroundColor Cyan
switch ($PsCmdlet.ParameterSetName)
{
"School No Null" { "$School/*,$($SomeThing.IsPresent)"; break}
"Class No Null" { "*/$Class,$($SomeThing.IsPresent)"; break}
"Class And School" { "$School/$Class,$($SomeThing.IsPresent)"; break}
}
}
Get-Students -Class "A"
Get-Students -School "West" -SomeThing
Get-Students -Class "A" -School "West"
### errors raised:
# Get-Students
### Parameter set cannot be resolved using the specified named parameters.
### + FullyQualifiedErrorId : AmbiguousParameterSet,Get-Students
# Get-Students -Class ""
# Get-Students -School ""
### Cannot validate argument on parameter '…'. The argument is null or empty.
### + FullyQualifiedErrorId : ParameterArgumentValidationError,Get-Students
原始答案(基于 PowerShell V2:ParameterSets 文章,来自 PowerShell Team Blog 和
Original answer (a code snippet based on PowerShell V2: ParameterSets article from PowerShell Team Blog and on MSDN help article) does not allow supplying both -Class
and -School
parameters all together:
function Get-Students{
param(
[parameter(Mandatory=$true, ParameterSetName="School No Null")][ValidateNotNullOrEmpty()]
[parameter(Mandatory=$false, ParameterSetName="Class No Null")] #[AllowNull()]
[string]$School,
[parameter(Mandatory=$true, ParameterSetName="Class No Null")] [ValidateNotNullOrEmpty()]
[parameter(Mandatory=$false, ParameterSetName="School No Null")]#[AllowNull()]
[string]$Class
)
Write-Host $PsCmdlet.ParameterSetName -ForegroundColor Cyan
switch ($PsCmdlet.ParameterSetName)
{
"School No Null" { $School; break}
"Class No Null" { $Class; break}
}
}
### valid calls:
Get-Students -Class "A"
Get-Students -School "West"
### errors raised:
### Parameter set cannot be resolved using the specified named parameters.
# Get-Students
# Get-Students -Class "A" -School "West"
### The argument is null or empty.
# Get-Students -Class ""
# Get-Students -School ""
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